1. Technical Field
The present invention relates Near Field Communication (NFC) Radio Frequency Identification (RFID) technology and, more particularly, to providing contact-less data transfer capabilities between two data-carrying devices, a reader (Initiator) and a receiver (Target).
2. Discussion of Related Art
For background information on the present invention the reader is referred to a white paper entitled “Near Field Communication” published by ECMA International under document number ECMA/TC32-TG19/2004/1. That document shows near field communication equipped devices brought into close proximity in order to exchange parameters necessary for setting up a communication with more bandwidth using a secondary communication technology, other than NFC, such as Wireless LAN (WLAN) or Bluetooth® communication. An NFC reader device initializes data transfer and issues a data exchange request to an NFC Target device. The target device can be a powerless memory card or an intelligent RFID device capable of data processing itself. Memory card based solutions are traditionally used in ticketing application while an emerging standard for RFID device to RFID-device communication has been specified by ECMA-340 (see also ISO/IEC 18092 (2004) and ETSI EN 302 190 v1.1.1 (2005-02)). These documents are all quite similar and are all titled “Near Field Communication Interface Protocol (NFCIP-1)” and define a half-duplex data exchange protocol between two devices. Some companies have decided to use NFCIP as an RFID protocol to be supported in their portable devices, such as mobile terminals. However, the concept can be enlarged to embrace non-portable devices as well. In other words, a portable device could be brought into close proximity to a non-portable device and the devices would exchange information using a radio transport mechanism according to the NFC specification. Thus RFID-based data transfer between NFC Forum compliant terminals can be foreseen as involving many different kinds of consumer electronics devices such as TVs, digiboxes, etc.
The nature of this kind of RFID communication is ‘touch’ based where an RFID target device is held for a relatively short time in the RFID reader device's interrogation field. The ‘touch’ paradigm is based on user experience analysis where a ‘touch’ action measured in time should be equal to or less than 0.5 seconds. Thus, NFC RFID is only suitable for exchanging small data items where a transfer can be completed in a reasonably short time interval (less than 0.5 seconds). For larger data items it is preferred to utilize alternative transport mechanisms available in the portable device (e.g. mobile telephone or terminal device) such as WLAN or Bluetooth technology. In many cases, RFID can be seen as a user input enhancement where instead of requesting user guidance to manually create a connection between devices, RFID communication is used to exchange communication details by just touching two devices. Creating such communication requires devices to be able to carry out a relatively fast capability negotiation, i.e., during the RFID ‘touch.’
Rules for communication can be contemplated where the NFC Initiator device is always sending request message and the NFC Target device is responding to requests with response messages. However, optimally, the capability negotiation between two devices should happen in one message pair, i.e., requiring only a request from the Initiator and a response from the Target device.
To fulfill such minimal timing requirements for the initial RFID ‘touch,’ there must be rules for exchanging data between the devices with correspondingly minimal data processing requirements. Ideally the responding device should be able to compose a default response beforehand in order to introduce as little overhead as possible to the RFID communication. To be capable of creating such a static message exchange, rules need to be defined on how communication is to be established and how service parameters are selected and communicated.
For NFC RFID communication no such solution exists.